1. Field of the Invention
The present invention relates to an antenna, more particularly, to a multi-band antenna which can be installed at the inner side of a notebook computer or else electronic products.
2. The Related Art
With the high-speed development of mobile communication technology and popularization of the electronic product, people hope more and more that notebook computer or other electronic products can receive and transmit the signals of different frequency bands. Electronic product having a dual-band antenna or a tri-band antenna is widely used in recent years. The antenna as a portion to receive and transmit a radio signal is used in communication products, the parameter measuring the performance of an antenna includes operation frequency, radiation pattern, reflected loss and antenna gain, etc.
Known antennas include the planar Inverted-F antenna, the monopole antenna and the loop antenna. Above-mentioned antennas are unable to use in different frequency bands, but the frequency bands used in the communication field include GSM850, EGSM, DCS1800, PCS1900, W-CDMA2100, etc. In some electronic products, different antennas from the above-mention antennas are combined in an electronic product to receive and transmit different band signals, but the antenna gain of the combined antennas will be reduced, because the signals produced by the corresponding antennas will interfere each other. And the combined antennas will occupy a large space in the electronic product. In addition, as the volume of the electronic product reduces, an antenna receiving and transmitting different band signals and having a smaller volume is more and more urgently needed.